Cemented Tungsten Carbide Hardmetal-An Introduction

Fang, Zhigang Zak; Koopman, M.; Wang, Hong-Tao

doi:10.1016/b978-0-08-096527-7.00004-0

Cited by 32 publications

(20 citation statements)

References 32 publications

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“…Cemented carbides enjoy great practical significance and have been extensively applied as rock drill buttons, pressing dies, cutting tools, and other abrasion-resistant engineering parts due to their combinations of considerable toughness, strength, and wear resistance [ 1 – 5 ]. The tungsten carbide phase endows the alloy excellent hardness as well as superior wear resistance, while the binder phase is responsible for strength and toughness of the composite materials.…”

Section: Introductionmentioning

confidence: 99%

A Review on Binderless Tungsten Carbide: Development and Application

et al. 2019

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HIGHLIGHTS• Establish processing-composition-microstructure-property relationships governing binderless tungsten carbide (BTC).• Highlight the densification improving strategies and toughening methods for BTC.• Provide key challenges as well as the outlook for superior peformance associated with BTC.ABSTRACT WC-Co alloys have enjoyed great practical significance owing to their excellent properties during the past decades. Despite the advantages, however, recently there have been concerns about the challenges associated with the use of Co, i.e. price instability, toxicity and properties degeneration, which necessitates the fabrication of binderless tungsten carbide (BTC). On the other hand, BTC or BTC composites, none of them, to date has been commercialized and produced on an industrial scale, but only used to a limited extent for specialized applications, such as mechanical seals undergoing high burthen as well as high temperature electrical contacts. There are two challenges in developing BTC: fully densifying the sintered body together with achieving a high toughness. Thus, this review applies towards comprehensively summarize the current knowledge of sintering behavior, microstructure, and mechanical properties of BTC, highlighting the densification improving strategies as well as toughening methods, so as to provide reference for those who would like to enhance the performance of BTC with better reliability advancing them to further wide applications and prepare the material in a way that is environment friendly, harmless to human health and low in production cost. This paper shows that the fabrication of highly dense and high-performance BTC is economically and technically feasible. The properties of BTC can be tailored by judiciously selecting the chemical composition coupled with taking into careful account the effects of processing techniques and parameters.

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Section: Introductionmentioning

confidence: 99%

A Review on Binderless Tungsten Carbide: Development and Application

et al. 2019

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“…In the case of cutting tools, the final product usually includes machining to the desired geometry and coating deposition to achieve improved wear resistance during service [10][11][12]. Diamond wheel grinding has been the industrial primary choice for machining the hardmetals.…”

Section: Introductionmentioning

confidence: 99%

Mechanical strength of ground WC-Co cemented carbides after coating deposition

Yang

Odén

Johansson-Jöesaar

et al. 2017

Materials Science and Engineering: A

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Manufacturing of hardmetal tools often involves surface grinding, ion etching and final coating.Each stage throughout the manufacturing chain introduces surface integrity changes which may be critical for defining the final mechanical behavior of the coated tools. Within this context, an experimental test program has been developed to assess the influence of a coating (TiN) deposition on surface integrity and transverse rupture strength of a previously ground finegrained WC-Co grade substrate. Four different substrate surface finish conditions (prior to ion etching and coating) were evaluated: as sintered (AS), ground (G), polished (P), and ground plus high temperature annealing (GTT). Surface integrity and fracture resistance characterization, complemented with a detailed fractographic analysis, were performed on both uncoated and coated samples. Results show that the surface integrity after grinding has been partly modified during the ion etching and film deposition processes, particularly in terms of a reduced compressive residual stress state at the substrate surface level. Consequently, the grinding induced strength enhancement in hardmetals is reduced for coated specimens. Main reason behind it is the change of nature, location and stress state acting on critical flaw: from processing defects existing at the subsurface (uncoated G specimens) to grinding-induced microcracks located close to the interface between coating and substrate, but within the subsurface of the 1 Current address: AMES-Sintered Metal Components, Camí de Can Ubach, 8, Pol. Ind. ¨Les Fallulles¨, 08620 -Sant Vicenç dels Horts, Barcelona -Spain latter (coated G specimens). This is not the case for AS and P conditions, where flexural strength does not change as a result of ion etching and coating. Finally, fracture resistance increases slightly for GTT specimens after coating process, possibly caused by a beneficial effect of the deposited film on the residual stress state at the surface.

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“…The main advantages of depositing such coatings are better protection against mechanical and thermal loads, superior wear resistance, and chemical stability, i.e. the surface can withstand a higher tool speed and less lubricant usage [2][3][4][5].…”

Section: Introductionmentioning

confidence: 99%

Contact damage resistance of TiN-coated hardmetals: Beneficial effects associated with substrate grinding

Yang

Marro

Trifonov

et al. 2015

Surface and Coatings Technology

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Contact loading is a common service condition for coated hardmetal tools and components. Substrate grinding represents a key step within the manufacturing chain of these coated systems. Within this context, the influence of surface integrity changes caused by abrasive grinding of the hardmetal substrate, prior to coating, is evaluated with respect to contact damage resistance. Three different substrate surface finish conditions are studied: ground (G), mirror-like polished (P) and ground plus heat-treated (GTT). Tests are conducted by means of spherical indentation under increasing monotonic load and the contact damage resistance is assessed. Substrate grinding enhances resistance against both crack nucleation at the coating surface and subsequent propagation into the hardmetal substrate. Hence, crack emergence and damage evolution is effectively delayed for the coated G condition, as compared to the reference P one. The observed system response is discussed on the basis of the beneficial effects associated with compressive residual stresses remnant at the subsurface level after grinding, ion-etching, and coating. The influence of the stress state is further corroborated by a lower resistance against damage for the coated GTT specimens. Finally, it is proposed and preliminary validated that substrate grinding also enhances damage tolerance of the coated system when exposed to contact loads. M.P. Johansson-Jõesaar and L. LlanesDear Professor Matthews, Please find attached electronic files corresponding to our contribution on contact damage resistance of TiN-coated hardmetals: beneficial effects associated with substrate grinding, which we (all authors do agree to the submission of the manuscript) offer for publication in Surface and Coatings Technology.I hope it is found satisfactory. (Procedia CIRP, Volume 13, 2014, Pages 257-263).(Authors) R1 is right about connection between results published in our contribution to the 2nd CIRP Conference on Surface Integrity (reference [27] in the submitted manuscript) and those presented in this paper. However, the two papers are distinctly different and cover completely different research topics and contain different data. The former focuses on "ground hardmetals" and "flexural strength/fractography", whereas the current one deals with "coated hardmetals" and "contact damage". Hence, we find R1's comment regarding "similar results" inappropriate. (Authors) Co binder effects on residual stresses are not neglected, and our writing may be blamed for such misunderstanding. Residual stresses induced by grinding are "macrostresses" evaluated in the WC phase and assumed to be representative of the whole WC-Co composite. They are different from the "microstresses" (different for each individual phase) that arise due to the difference in thermal expansion between the binder and the carbide as the material cools from liquid-or solid-phase sintering. In cemented carbides with WC as the carbide, the WC is taken as a reliable reference phase because it remains stoichiometric...

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Cemented Tungsten Carbide Hardmetal-An Introduction

Cited by 32 publications

References 32 publications

A Review on Binderless Tungsten Carbide: Development and Application

A Review on Binderless Tungsten Carbide: Development and Application

Mechanical strength of ground WC-Co cemented carbides after coating deposition

Contact damage resistance of TiN-coated hardmetals: Beneficial effects associated with substrate grinding

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